Synonym of "High-Level" in "High-Level Ideas/Description/Method"

Solution 1:

It seems to me that high-level description is somewhat redundant. I know it's possible to have a detailed description, but if description is used on its own, without qualification, I would assume it would be high-level anyway.

From Merriam-Webster's definition of description:

1 b : a statement or account giving the characteristics of someone or something : a descriptive statement or account
       // The review was little more than a description of the film's plot.

As such, I see nothing wrong with just the following:

a description of the method

However, if some kind of qualification is required, you could used general rather than high-level:

[Merriam-Webster]
6 : relating to, determined by, or concerned with main elements rather than limited details
    // bearing a general resemblance to the original

Using general is more understandable than high-level, which might not necessarily be easily understood by everyone:

a general description of the method

To provide contrast to general description, add what was mentioned in the definition of general as contrasting with it:

See Section 1.3.4 for a general description of the method and Section 2.1 for details of the specific application.